Electrical storage devices in implantables are usually batteries, which may or may not be rechargeable. Capacitances have been used within implanted devices for various purposes, such as to provide signal demodulation, detection, filtering, and to remove unwanted alternating currents, but it is not believed that electrolytic, capacitive electrodes. disposed in body fluids, have been previously used to store the electrical energy needed for operating the internal electrical circuitry of an implantable device.
Various investigators have used an electrolytic, capacitor electrode to conduct electrical energy for a stimulating pulse. An article by Guyton and Hambrecht, entitled "Theory and design of capacitor electrodes for chronic stimulation", in Medical and Biological Engineering, Sep. 1974, page 613 and following, discloses and discusses such a system. In that case, the electrode also serves as the stimulating electrode. A counterelectrode, which adds to the storage capacitance, has also been used with such electrolytic, capacitor electrode, and such counterelectrode has also served as the other, stimulating electrode.
U.S. Pat. No. 4,934,368, for Multi-Electrode Neurological Stimulation Apparatus, inventor, H. Wilfred Lynch, shows, in FIG. 19, a storage capacitor which provides electrical energy to control and demultiplexing electronics, which includes a shift register. An electrolytic storage capacitor, disposed in body fluids, is not suggested. It is proposed in that patent that the capacitor be kept small so as not to interfere with the stimulating pulse.